An Unusual Electrochemical Reductive Cleavage of Azo Dye into Highly Redox Active Copolymeric Aniline Derivatives on a MWCNT Modified Electrode Surface at Neutral pH and Its Electroanalytical Features

Developments of new decomposition or degradation methods of environmentally hazardous azo dyes from textile industries are very important. Usually, strong acid-based chemical/electrochemical and neutral pH-based bacterial decomposition methods were widely used. Here, we report a mild, simple, and facile electrochemical method for decomposition of azo dye (Sudan yellow; SY) into a highly redox active copolymer of polyanilines via aniline derivatives as intermediates on a MWCNT modified glassy carbon electrode (GCE/MWCNT) surface unusually in a neutral pH using phosphate buffer solution (PBS) (GCE/MWCNT@SY-CoPANIpH7). One of the intermediate products, aniline (Mw = 93 mol g–1, calculated) was identified by an in situ cyclic voltammetry-electrochemical quartz crystal balance experiment. No such SY electrochemical reaction was observed on a naked GCE surface. Physico-chemical characterizations by TEM, Raman, IR, and UV–vis spectroscopic methods supported the formation of polymeric product on MWCNT surface (GC...